1. Field of the Invention
The present invention relates to an apparatus for controlling a degree of opening of a throttle valve for a vehicle.
2. Description of Related Art
As one of conventional methods of controlling a driving state of a vehicle is a traction control that is a control for reducing or converging degrees of slippage by decreasing a driving torque of driven wheels, for example, by means of braking or reducing an engine output when a degree of slippage of a driven wheel on pavement exceeds a predetermined value-specifically, when a slip ratio specified by a balance of rotations of the driven and undriven wheels exceeds a given value.
A method of reducing the engine output is disclosed, for example, in Japanese Patent Publication (laid-open) No. 22,948/ 1982 where it is described such that a degree of opening of a throttle valve for an engine is forcibly reduced separately from operation of stepping an accelerator pedal down when a slippage has occurred, thereby controlling the engine output.
This known method suffers from the disadvantage, however, that a control over a degree of opening of the throttle valve at the time of traction control is implemented using a hydraulic mechanism which is complicated and is likely to raise a cost.